28876781 has 2 divisors, whose sum is σ = 28876782. Its totient is φ = 28876780.

The previous prime is 28876747. The next prime is 28876807. The reversal of 28876781 is 18767882.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25300900 + 3575881 = 5030^2 + 1891^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28876781 is a prime.

It is a super-2 number, since 2×28876781² = 1667736961843922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28876711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14438390 + 14438391.

It is an arithmetic number, because the mean of its divisors is an integer number (14438391).

Almost surely, 2^28876781 is an apocalyptic number.

It is an amenable number.

28876781 is a deficient number, since it is larger than the sum of its proper divisors (1).

28876781 is an equidigital number, since it uses as much as digits as its factorization.

28876781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 301056, while the sum is 47.

The square root of 28876781 is about 5373.7120317337. The cubic root of 28876781 is about 306.7959294126.

The spelling of 28876781 in words is "twenty-eight million, eight hundred seventy-six thousand, seven hundred eighty-one".